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\usepackage{tikz,graphicx,subfig,caption} % Required for drawing custom shapes
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\usepackage{indentfirst}
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\begin{document}
	\begin{tikzpicture}[>=latex,every node/.style={anchor=south west,,inner sep=0,fill=white}]
		\node(text)[anchor=north,align=left,fill=pink!20, inner sep=0.3em] at (0,0){  
			$\ast\ $通过查看“{\textcolor{blue}{当前单词}}”,是否可以解决？为此：\\
			\ \ \ \ {\textcolor{blue}{求：}}{\textcolor{red}{$follow(A)=$}}{b}\ \ \ \ {\textcolor{blue}{看到：}}$\{b\}\cap\{c\}=\Phi$;\\
			{\textcolor{blue}{$\therefore$ \  若w=c则c5;若w=b则r(3)}。}
		};
	\end{tikzpicture}
\end{document}